The present invention relates to a method and apparatus for secure data transfer between a communication device and an application server in a wireless network, and more particularly to a method for secure data transfer between a communication device, provided with a SIM card, and an application server in a wireless network using WAP (Wireless Application Protocol) for the data transfer, wherein said SIM card contains a secret/private key, an algorithm for signing of data, a SAT application for handling the signing dialogue and the signing of data.
Several protocols for data transfer over wireless networks have been proposed by different mobile phone manufactures. Ericsson, Motorola, Nokia Mobile Phones, and Uniwired Planet have developed a joint standard called Wireless Application Protocol (WAP). The purpose of the Wireless Application Protocol is to provide operators, infrastructure and terminal manufactures, and content developers a common environment enabling development of advanced services for digital mobile phones and other wireless terminals or portable communication devices. For example, the WAP enables e-mail and Internet access from a digital mobile phone.
Certain services and WAP applications provided via Internet, such as ordering, order confirmations, bank services, etc, and associated transactions require a high level of security.
WO 99/01848 discloses a procedure, which is applicable for the control of keys to applications making use of the subscriber identity module (SIM) in a mobile phone and for the control of license agreements concerning the use of such applications. Further, the procedure provides data security that allows safeguarding of the interests of the operator, module manufacturer, application developers and users of applications. A key list comprising one or more application-specific keys is stored in the subscriber identity module. A corresponding list is also stored in an application control server connected to the network, which takes care of the control of applications stored in subscriber identity modules. The application stored in the subscriber identity module is activated and/or closed by using the key list.
DE-A1-198 16 575 describes a method for running special applications, such as a virtual charge card, entirely or partly, in a SXM. Further, it is suggested using the SIM toolkit as a means for communication. Security is provided by means of the conventional security means and procedure of the SIM-card. For example, an anti theft security for the special application authorization and the service data in combination with one or more PIN-codes of the SIM-card.
WO 98/37663 discloses a method for checking authorisation incorporating a way to impart to a smart card an encryption key and including a way to cause a microprocessor, by means of the encryption key and at least one number, to perform a calculation whose result comprises a first signature. The signature together with said number are transferred to a system for which authorisation is to be shown which includes a computer in which said encryption key is stored. The computer is programmed to carry out the calculation to obtain the signature and then to compare the latter signature with the first signature for the verification.
In the above mentioned methods all information transfer is done through SAT (SIM Application Toolkit) applications, in which the security solution also is implemented.
Another way of solving the security problem is to provide one-time password pads, wherein a “new” password is entered via the key pad of the mobile phone or the communication device every time an application is used.
There are several problems and disadvantages associated with the above mentioned prior art solutions. The security level is to low for higher values: passwords could be discovered and the password has to be entered manually making WAP applications very user unfriendly compared to for example pure SAT applications and, of course, the password has to be remembered.
It is an object of the present invention to provide an improved method and system for executing secure data transfer between a communication device, provided with a smart card, such as a SIM card, and an application server in a wireless network using a data transfer protocol such as WAP (Wireless Application Protocol) for the data transfer.
This in accomplished by a method and system according to the invention for executing secure data transfer on the application level for communication applications executing on mobile phones according to the invention. The smart card contains a secret/private key, an algorithm for signing of data, a signing application for handling the signing dialogue and the signing of data. A communication application, such as a WAP application, is installed on the communication device enabling communication with the application server by means of a dialogue, and information browsing on the server is initiated from the communication device, wherein data are transferred between the server and the communication device. Further, a request requiring a secure transaction of data is send from the communication device to the server, and an agreement proposal for the secure transaction is send from the server to the communication device. If the agreement proposal in considered acceptable, the agreement proposal is returned to a security adapter. The WAP application in the communication device is suspended or terminated. Details of the transaction to be secured and a sign request are entered into at least a message, such as SMS or USSD packets, from the adapter to the smart card in the communication device in order to activate the signing application. The details of the transaction and a prompt for an accept are displayed on the communication device. If the transaction is accepted, the signing-application signs the data to be send with the secret/private key by using the algorithm, the signed data are send from the communication device to the security adapter via messages. The signature is verified and the verified signed data are send to the server for the final execution of the transaction.
Another object of the invention is to provide an apparatus for connection to a wireless network for monitoring the data transfer between the communication device and the application server.
This is accomplished by a security adapter according to the invention, providing a high level of security in data transfer on the application level for communication applications executing on communication devices.
An advantage of the present invention is that a high level of security in the data transfer is achieved in combination with conventional WAP browsing. An additional advantage is that the application on the SIM card can be made very thin and flexible, because it only has to handle signing of data and no information or menu handling. Further, the system handling the information browning and the system handling the security of the transacrtions are separated and, therefore, they can be uppdated and changed independently.